require 'rubygems'
require 'open4'

pid, stdin, stdout, stderr = Open4::popen4("ruby background.rb")

begin
  10.times do |n|
    puts "Foreground: #{Time.now}"
    sleep(1)
  end
rescue Interrupt # someone did CTRL-C
end

def kill
  puts "Killing child"
  Process.kill(Signal.list['TERM'], pid)
end

at_exit do
  kill
end